In a storage subsystem, a plurality of logical storage devices to which storage areas of a plurality of storage devices are allocated are provided in a recognizable manner to a host computer, whereby the host computer is able to perform the I/O processing of data to the relevant logical storage device.
When a storage subsystem receives an I/O request from a host computer, a microprocessor provided in the storage subsystem controls the I/O processing according to the I/O request; for instance, data write processing of writing data into a storage device, and data read processing of reading data from a storage device.
Among these kinds of storage subsystems, proposed is a type comprising a plurality of controllers including a plurality of microprocessors and a local memory for executing I/O processing with a storage device, and further comprising a management table for managing the controller to handle the I/O processing to the logical storage area of the storage device (refer to PTL 1).
With the system described in PTL 1, for instance, if a host computer issues an I/O request to a logical storage area of a storage device via a port, a host interface unit specifies the controller to handle the I/O processing of the logical storage area of the storage device based on a management table, transfers the I/O request to the specified controller, and any one of the microprocessors in the controller that received the I/O request executes the I/O processing to the logical storage area of the storage device.
According to the system described in PTL 1, since the correspondence of the logical storage area of the storage device and the respective controllers is managed with the management table, the correspondence of the logical storage area of the storage device and the respective controllers can be set arbitrarily, and the microprocessor to handle the processing of the I/O request can be arbitrarily set among the plurality of microprocessors in the controller without having to fix the correspondence of the port and the microprocessor.